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Southern Water Services Limited – AMP8 Keycol WSW – Nitrate

Notice under regulation 28(4) of the Water Supply (Water Quality) Regulations 2016 (as amended)

Reference: SRN-2023-00014

Version Number: 2

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): Southern Water Services Limited, with registered number 02366670 (hereinafter called ‘the Company’).

Assets Affected:

  • Keycol WSW – TK009
  • Medway East Supply System – Y016

Details of this Notice:

  1. The Drinking Water Inspectorate (‘the Inspectorate’) has received a regulation 28(1) report of the Water Supply (Water Quality) Regulations 2016 (as amended) (‘the Regulations’) from the Company dated 23 March 2023 which states that there is or has been a significant risk of supplying water from Keycol WSW (and associated assets as applicable) that could constitute a potential danger to human health or could be unwholesome.
  2. Consequently, this Notice is served on the Company by the Inspectorate on behalf of the Secretary of State, under regulation 28(4) for the assets listed above, for risks associated with:

Table 1: Table of the hazards, hazardous events, and/or parameters covered by this Notice, including the Hazard I D numbers and the description of risks.

Description of Risk

Hazard/ Hazardous Event/ Parameter

Hazard I D

Increasing trend for nitrate in raw water.

Nitrate

40401

  1. The Company are required to satisfy the following requirements.

The date given is that until or by which the requirements must be maintained or satisfied, as appropriate.

Requirements:

(a) To maintain the following measures for the period specified in each case:

  1. Enhanced sampling and monitoring for nitrate (once available) of all high-risk raw water sources and associated final waters on a weekly basis to supplement the current regulatory treated water monitoring.
    Date: Ongoing for the duration of this Notice.
  2. Report all exceedances of the nitrate parameter to the Local Authority and Health Protection team and agree further additional steps to protect public health as appropriate.
    Date: Ongoing for the duration of this Notice.
  3. Report all regulatory exceedances of the standards for the nitrate parameter in mg/l NO3 to DWI as part of current monthly exception reporting process.
    Date: Ongoing for the duration of this Notice.
  4. Carry out maintenance, validation and calibration of all online nitrate monitors installed (once available), at sites covered by this notice, at the frequency outlined within company procedures.
    Date: Ongoing for the duration of this Notice.
  5. When Keycol WSW is in supply, continue to follow the nitrate operating plan.
    Date: Ongoing for the duration of this Notice.
  6. Continue ongoing catchment management for Nitrate.
    Date: Ongoing for the duration of this Notice.

(b) To review, revise or make operational the following measures, by the dates specified in each case:

  1. Confirm that Keycol WSW has been fully isolated from supply.
    Date: 31 July 2026.
  2. Confirm the plan for Keycol WSW in the context of the integrated Water Resources Management Plan (WRMP) for the area, detailing how the risk of nitrates will be mitigated.
    Date: 31 March 2030.

(c) To audit whether the measures have been effective by the following means:

  1. Define an audit strategy to monitor the effectiveness of the measures specified in sections (a) and (b).
    Date: 31 March 2026.
  2. Implement, and keep under continuous review, the audit strategy defined in measure (c)1.
    Date: Following completion of measure (c)1. onwards.

(d) Not to supply water for regulation 4(1) purposes from Keycol WSW, or not to so supply unless the specified conditions below are satisfied:

  1. Keycol WSW will not be returned to service until all relevant issues associated with Nitrate risks have been remediated.
    Date: Ongoing for the duration of this notice.

(e) To provide the following information in the time and manner specified below to enable monitoring of progress towards the mitigation of the risks:

  1. Provide a progress report annually.
    Date: by 31 January each year.
  2. Provide a report evidencing that Keycol WSW is isolated from supply.
    Date: 30 August 2026.
  3. Provide a report confirming Provide a report confirming the Company’s plan for Keycol WSW in AMP 9 in the context of the integrated Water Resources Management Plan for the area, detailing how the risk of nitrates will be mitigated.
    Date: 30 April 2030.
  4. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
    Date: 30 April 2026.
  5. Submit any revisions of the audit strategy produced under measure (c)2.
    Date: Within 1 month of a revision.
  6. Submit a report in the event that any completed measures of this Notice need to be altered in any way, for any reason.
    Date: Ongoing for the duration of this Notice.
  7. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
    Date: 30 April 2030.

Further Details of this Notice:

  1. Any product or substance used as a result of the requirements in this Notice must comply with regulation 31.
  2. Under regulation 28(6) the Inspectorate, on behalf of the Secretary of State, may by notice served on the Company, revoke or vary this Notice.
  3. Failure by the Company to comply with this Notice may result in enforcement proceedings under section 18 of the Water Industry Act 1991 (as amended).

Signed

Nicholas Adjei
Deputy Chief Inspector, on behalf of the Secretary of State for Environment, Food and Rural Affairs
9 February 2026
Reference: SRN-2023-00014 v2

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